1. Technical Field
The present disclosure relates to storage area networks.
2. Description of the Related Art
Storage Area Networks (SANs) are computer systems in which large mass storage devices such as Redundant Array of Independent Disks (RAID) devices are connected to a central processor or processors via high-speed network technology (as opposed to, for example, via a system bus). SANs are increasingly used to store vast amounts of information and their usage has grown exponentially with the rise of the Internet.
There are two general ways to implement SANs: centralized and decentralized. A centralized SAN ties multiple hosts into a single storage system with large amounts of cache and redundant power supplies. FIG. 1 illustrates a typical centralized SAN. Initiators, also known as hosts 100, 102, 104 communicate with a large mass storage device 106, also known as targets.
A decentralized SAN, on the other hand, connects multiple mass storage devices with a centralized controller, such as a switch, that coordinates storage between the hosts and the multiple mass storage devices. FIG. 2 illustrates a typical distributed SAN. Here, initiators 200, 202, 204 communicate with a virtual SAN comprised of a number of large mass storage devices 206, 208, 210 via a switch 212.
There are a number of various applications that can be utilized within a SAN, for example, volume management applications, data replication applications, data migration applications, and data protection applications. These applications are operated at either the host side or the storage side.
In low-bandwidth environments, the available resources were simply assigned to hosts as needed or requested. A high-bandwidth storage area network environment, however, opens up the possibility of assigning available resources in a manner that might make more sense from either the business or technical standpoint.